Long-term anoxia and release of ancient, labile carbon upon thaw of Pleistocene permafrost

Geophysical Research Letters
By: , and 

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Abstract

The fate of permafrost carbon upon thaw will drive feedbacks to climate warming. Here we consider the character and context of dissolved organic carbon (DOC) in yedoma permafrost cores from up to 20 m depth in central Alaska. We observed high DOC concentrations (4 to 129 mM) and consistent low molecular weight organic acid concentrations in three cores. We estimate a DOC production rate of 12 µmol DOC m−2 yr−1 based on model ages of up to ~200 kyr derived from uranium isotopes. Acetate C accounted for 24 ± 1% of DOC in all samples. This proportion suggests long-term anaerobiosis and is likely to influence thaw outcomes due to biolability of acetate upon release in many environments. The combination of uranium isotopes, ammonium concentrations, and calcium concentrations explained 86% of the variation in thaw water DOC concentrations, suggesting that DOC production may be related to both reducing conditions and mineral dissolution over time.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Long-term anoxia and release of ancient, labile carbon upon thaw of Pleistocene permafrost
Series title Geophysical Research Letters
DOI 10.1002/2015GL066296
Volume 42
Issue 24
Year Published 2015
Language English
Publisher AGU
Contributing office(s) National Research Program - Central Branch
Description 9 p.
First page 10730
Last page 10738
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